PJB-2013-372
GLU-DT1 ALLELIC VARIATION IN SYNTHETIC HEXAPLOID WHEATS DERIVED FROM DURUM CULTIVAR ‘DECOY’ × AEGILOPS TAUSCHII ACCESSIONAL CROSSES
MADEEHA KHALID1, TARIQ MAHMOOD1, AWAIS RASHEED1*, ALVINA GUL KAZI2, AHMAD ALI3 AND ABDUL MUJEEB KAZI4
Abstract
Characterization of high molecular weight glutenin subunits is the fundamental approach for categorizing genotypes with good bread making quality. Allelic variation at Glu-Dt1 locus is major determinant of bread wheat end use quality. In synthetic hexaploid wheats (SHWs), the D-genome encodes numerous allelic variants of high molecular weight glutenin subunits that require appropriate identification prior to their exploitation for wheat improvement. This study was conducted to identify allelic variation at Glu-Dt1 locus of 47 accessions of D-genome synthetic wheats derived from the crossing of durum cultivar “Decoy” with different accessions of Aegilops tauschii. Biochemical (SDS-PAGE) and molecular marker techniques were used to stringently characterize allelic differentiation. Nine different alleles at Glu-Dt1 locus were observed which formed 13 different subunit combinations. The frequency of inferior quality encoding allele, 1Dx2+1Dy12, was equivalent (21.27%) to the frequency of superior quality encoding allele, 1Dx5+1Dy10 (21.27%). Additional validation was carried out with co-dominant molecular markers for Glu-A1c (Null), Glu-D1d (1Dx5+1Dy10), Glu-D1a (1Dx2+1Dy12) and Glu-D1-1g (1Dx2.1) alleles. The high number of glutenin subunits observed in SHWs are suggestive that somewhat narrow genetic base for D-genome encoded glutenin subunits in bread wheat may be broadened by exploiting this diploid genomic grass resource through targeting allelic transfers from synthetic hexaploid genetic stocks. The identification of these new allelic combinations in SHWs provide an option to replace other inferior quality encoding alleles in bread wheat cultivarsby better allelic variants that have become available at the Glu-Dt1 locus of SHWs being inherited from diverse Ae. tauschii accessions.
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